Rotor for homogenizers



May 27, 1952 N. VON KORSHENEWSKY 8,

ROTOR FOR HOMOGENIZERS Filed Aug. 25, 1950,

INVENTOR.

A ma/u Von! A azrasn/z-wm Patented May 27, 1952 ROTOR FOR HOMOGENIZERS Nicolai von Korshenewsky, Stockholm, Sweden, assignor to A. B. Strateg, Lidingo, Sweden Application August 25, 1950, Serial N 0. 181,402 In Switzerland October 20, 1949 9 Claims.

Apparatuses for mixing or homogenizing different liquid or viscous substances are frequently constructed in a similar way as centrifugal apparatuses, a rotating disc, the so-called rotor, being rotated at high speed in a container into which the substances to be homogenized have been introduced. Hereby the substances introduced are subjected to the action of centrifugal forces, whereby they are flung against the walls of the container and mixed with each other in pulverized condition.

The construction of the rotor plays a very important role for the effect to be obtained as the rotor may be said to have the function of grinding the substances to be mixed and of combining the very fine particles into a homogeneous mass.

In the rotors used so far the hydromechanical physical points 'ofview have not been suificiently considered. The present invention aims at utilizing various phenomena and effects arising in liquid streams. The most important factor is to bring about a suitable surface. The rotor is therefore provided with a plurality of grooves or furrows either on one or on both sides of its circular surface. Such grooves perform a double effect: on the one hand the total surface area is hereby increased, causing a greater part of the substances to be treated to adhere to the surface and to be simultaneously rotated; on the other hand the edges of the grooves perform a specific effect. It is known from hydrodynamics that a considerable increase of velocity is obtained at such places Where continuous streams are forced to flow around a sharp edge. Hereby a tearing of the liquid films is brought about at these places. Considering that the rotor ordinarily rotates at great speed and that the final product is rapidly discharged from the homogenizer it is obviously important to bring about such tearings as often as possible during the time in which the liquid films are on the rotor surface. For this purpose both a great number of sharp-edged grooves and the most advantageous disposition of the grooves is required.

A further increase of the homogenizing elfect is obtained by providing the rotor with a plurality of the narrowest possible channels transversely extending through the rotor such as to allow the passage of the substances to be mixed from one side of the rotor to the other. For, by the rotational movement flows are created which bring about subatmospheric pressures on one side of the rotor hereby sucking the liquid from the other side of the rotor through the channels in the rotor. By so designing the rotor two different homogenizing principles are combined with each other. Besides homogenizers with rotating discs of the type principally referred tom the present application there is also known a type in which the distribution and mixing effect is achieved by pressing the liquids through narrow nozzles. Such an additional novel effect is entailed by providing the rotor with the abov named holes or channels.

The invention is described in detail with reference to the embodiment shown in Figs.1 and 2 in plane view and in longitudinal section re.- s'pectively while Fig 3 shows in section a modification of the device. The rotor l is suitably madefrom non-corrosive metal. A number of grooves 2 form sharp edges with the rotor surface. These grooves 2 are disposed radially as conventional.

In addition, the rotor according to the invention is provided with a specific groove 4 disposed as a broken line along the edge of the rotor and concentrically in relation to the rotor shaft. The groove 4, instead of being in the form of a broken line, may also be of undulate shape. Such shapings of the groove 4 cause the edges to form an angle with the direction of rotation resulting in a particularly favourable effect upon the liquid layers moving along the rotor surface. Thus, a continuous tearing effect may be said to take place.

The numeral 3 designates the above mentioned narrow channels extending through the rotor, which channels may be disposed in axial direction or be slightly oblique to the rotational axis of the rotor.

In Fig. 2 the same parts are designated by the same numerals.

As appears from the drawings the rotor comprises a combination of features for increasing its effectiveness. By combining the various measures such as the circumferential grooves, the sharp edges, and the channels as a further advantage the possibility is obtained to reduce the dimensions of the apparatus as a whole to a great extent in comparison with conventional apparatuses. By providing a great number of liquid passages and by bringing about a tearing and pulverizing of the substances to be mixed due to the great number of closely spaced sharp edges the rotor can be made much smaller than in homogenizers as constructed so far. Of course the size of the rotor must be adapted to its rotational speed and its main field of use because the homogenizing effect is and must be different in quantity and quality for substances having different viscosities. In general it has appeared that a rotor according to the invention having a diameter less than 20 cm. is sufficient for all purposes. For homogenirers to be used for the preparation of milk products such as cream from fat or butter it is suflicient to use rotors having a diameter of about 10 cm. By increasing the rotational speed the rotor dimensions may be still further reduced whereby a handy small-sized apparatus is obtained.

It is thus apparent that the design of the rotor has decisive importance in the construction of homogenizers. The present invention which has been explained in connection with one specific embodiment may be varied in many ways if consideration is paid to the above indicated principles.

I claim:

1. A rotor for mixing machines of the type of homogenizers, said rotor comprising a flat circular cylinder provided with-a grooveon at least one of the circular surfaces of the rotor, said groovehaving sharp edgesand extending along an'undulate line concentric with the rotational axis ofthe rotor, and a plurality of narrow channels extending through the rotor in directions substantiallyparallel to the rotational axis.

2. The-rotor; as set forth in claim'L-in which on at least one of thecircular surfaces'equipped with said undulate concentric groove, a plurality ofsubstantially radially disposed grooves are provided.

3; The rotor asset forth in claim 2, in which said channels open into said radially disposed grooves.

4. Arotor for inixingmachines of the type of homogenizers, said rotor comprising a hatchcular cylinder provided with a groove-on at least one ofthe circular surfaces of the rotor, said groovehaving sharpedges and extending along a-zig-zag line concentric with the rotational axis of the rotor, and a plurality of narrow channels extending through the rotor in directions substantially parallel to the rotational axis.

5. The rotor, as set forth in claim 4, in which, on at least one of the circular surfaces equipped with said groove concentrically extending along a zig-zag line, a plurality of substantially radially disposed grooves are provided.-

6. The rotor as set forthin claim 5,-in which said channels open into said radially disposed grooves.

7. A rotor for mixing machines of the type of homogenizers, said rotor comprising a fiat circular cylinder provided with a groove on at least one of the circular surfaces of the rotor, said groove having sharp edges and extending along a broken line concentric with the rotational axis of the rotor, and a plurality of narrow channels extending through the rotor in directions slightly obliquely in relation'to the rotational axis.

8. The rotor, as set forth in claim 7, in which, on at least one of the circular surfaces equipped with .said broken concentric groove, a plurality of substantially radially disposed grooves are provided.

9. The rotor as set forth in claim 8, in which said channels open into said radially disposed grooves.

NICOLAI von KORSHEN'EWSKY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,624,037 Butter Apr. 12, 1927 2,163,150 Meissner June 20,1939 2,260,834 Everett Oct. 28, 1941 2,270,480 Seyfried Jan. 20, 1942 2,321,599 Hofimann June 15, 1943 

